Method of forming a heat exchange device



April l1, w39. J. KARMAZIN METHOD OF FORMING A HEAT EXCHANGE DEVICEFiled May 7, 1935 JEH/v KA INVENTQR A R/f/lZ//r XTTORNEY.

flexibility in manufacturing the devices in various being utilizedwhereby different lengths of header constructed according to the presentinvention: scope into the corresponding tubular projections METHOD oFFORMING a HEAT EXCHANGE DEVICE FFW@ -UNITI- John Karmazin, Huntington,Ind.; assignor to General Motors Corporation, Dayton, Ohio, a'corporation of Delaware Application May 7, 1935, Serial No. 20,206

3 claims. .(oi. .e9-157.3)

This invention relates to refrigerating appa- Fig. 4 is aperspective'view of a portion of the ratus and more particularly to anovel heat exheader construction at an intermediate state of changedevice for usein refrigeratiug apparatus manufacture; and for otherpurposes. Fig. 5 is a perspective view of the second por- Heretofore, inconstructing heat exchangers of tion of the header construction at anintermediate 5 the 'type comprising a plurality of parallel tubesstageof manufacture; .usually having fins thereon, the necessity of con-Fig. 6. is a perspective view of a portion of necting together the endsof the parallel tubes in another header construction shown in anintersome manner has presented a problem. For exmediate state ofmanufacture; and ample, if it is desired to connect the ends of a Fig.,7is a perspective view of anotherportion 10 plurality of tubes into asingle header for placof a header construction shown in -an intermeingthe tubes inparallel circuit Irelation,l the diate stage of manufacture.header constructions heretofore employed have Referring now to Fig. 1,the heat exchange necessitated the use of individual dies for eachdevice comprises a heat exchange core III which size of heat exchangerwhich is constructed. In is formed of a plurality of parallel tubes I2and 15 supplying the needs of the trade, it is necessary transverse finsI4. The heat exchange core may vthat a large range of sizes bemanufactured, due be formed in any suitable manner, the core illusto themany varied individual requirements imtrated .being formed from finshaving integral posed by the various applications for heat extapered:tubular projections formed therein and change structures. In meetingthese requiretelescoped vwith similar projections of adjacent ments,particularly for heat exchangers having fins to provide the continuoustubes I2. Such a their tubes connected in parallel circuit relation,coreconstruction is illustrated in' Vmore detail in the cost of thedifferent dies andv other machine the patent to Karmazin-l,997,563issued April 9, tools which must be constructed individually for 1935.At either end of the core I0, headers I6 each different size of heatexchanger has conand lI8 are provided to connect the tubes I2 in 25tributed materially to the high cost of such deparallel circuitrelation. Suitable inlet and out-- vices particularly where the numberproduced in let connections 20 and 22 are provided in the a given sizeis rather small. headers I6 and I8 respectively.

It is an object of the present invention to pro- Each of the headers I6and I8 are formed vide a heat exchange structure by which greatersomewhat similarly in order to admit of a process sizes is obtainedwithout prohibitive costior a for diierent heat exchangers do notnecessitate small production of a single size of heat exthe use ofindividual tooling for each length. changers. Thus, each header isformed from a' pair of More particularly, it is an object to provide achannel-like members which may be cut from a heat exchanger and headerconstruction therelong strip of channel-like material in any length for,by which the same set of manufacturing tools desired. The pair ofchannel-like members are and machinery maybe utilized for. producingtelescoped together in order to provide aclosed heat exchangers havingheaders of various lheader having openings for engagement with thelengths without the necessity of individual dies tubes of the heatexchanger core. The header I6, and tools for each individual length. forexample, may be formed from a pair'oi It is a furtherobject of theinvention to prolengths of channel-like strips 24 and 26 which 'videanovel method of producing heat exchangers are telescoped together asillustrated in Fig. 2. and headers therefor from sheet metal at low Thechannel-like strip may be formed in any of cost. ai number of ways, forexample, as by extrusion, -45 Further objects and advantages of thepresent orV by rolling or stamping from a flat strip. invention will beapparent from the following Either before-or after the strip is giventhe chandescription, reference being had to the accomnel-like form,suitable tubular projections 28 are panying drawing, whereinv apreferred form of formed therein at intervals corresponding to thepresent invention is clearly shown. the spacing of the tubes I2. Thetubular projec- In the drawing: tions 28 form openings to the header 'I6and in Fig. 1 is a view in elevation of heat exchanger the constructionillustrated are tapered to tele- Flg. 2 is a cross section on line 2--2of Fig. 1; lformed in the top fins I4 of the core. The chan- Fig. 3 is across section on line 3-3 of Fig. 2; nel-like strip from which themember 24 is cut 55 has a suitable opening formed therein by which theinlet connection 2li is secured to the header i6. The opening 30 ispreferably formed after the member 24 is cut from the strip of materialof channel-like form.

The header i8 is formed by a similar process to provide a pair ofchannel-like members 32 and 34 corresponding respectively to the members24 and 26. In the construction illustrated, the channel-like member 34is provided with a plurality of tubular projections 36 on the uppersurface thereof which are given a reverse taper to receive the taperedtubular projections of the lower-most iin I4. 'I'he cross sectionalshape of the channel-like members 24, 26, 32 and 34, in the forni of theinvention illustrated, is approximately that of a partial cylinder. Thatportion of the strip 2 6 and strip 28 between the openings orprojections 28 and 36 respectively may be either a continuation of thecylindrical arc as shown in Fig. 5 or may be fiat as shown in Fig. 7.When the protuberances 28 and 36 are formed after the strip is given itschannel-like form, it is convenient to use the construction illustratedin Fig'. 5. When the protuberances 28 and 36 are formed from the fiatstrip, it is more convenient to utilize the form illustrated in Fig. 7.It will be understood, of course, that various other cross sectionaliorms may be utilized so long as the outline of the assembledchannel-like members of the header provides a generally tubularstructure.

After the lengths of channel-like strip have been cut from .a longerpiece of the same, the members 24 and 26 are telescoped together and themembers 32 and 34 are telescoped together as illustrated in Fig. 2.Suitable end closures 38, preferably of stamped sheet metal, are nextapplied to the ends of the headers i6 and i8 and the inlet and outletconnections 2i? and 21T inserted in the opening 3i] and a correspondingopening formed in the channel-like member 32.

The headers I6 and iii are then assembled to the core i0 and the entirestructure bonded together by a suitable sealing medium. For example, theheat exchanger may be sealed by copper welding ina furnace having areducing atmosphere, or the structure may be sealed by a solder dip.While it is most convenient to seal the entire heat exchanger includingthe core I0 and the headers i6 and i8 at one operation, it may bedesirable in some cases to seal the headers i6 and I8 and the core lilindividually before assembling them together. Likewise, while the inletand outlet connections have been illustrated as connecting at anintermediate point along the length of the header, it may be desirablein some instances to connect the inlet and outlet connections at one endof the header, in which case the closure 33 at that end is omitted andthe inlet or outlet connection substituted therefor.

While the form oi' embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. The method of forming a heat exchange device which comprises thesteps of forming a header by forming a pair of channel-like strips, eachstrip having a substantially circular segmental cross-section and anopen longitudinal side and one strip having a plurality of tube engagingopenings with integral tubular flanges along one wall thereof,longitudinally telescoping said pair of short lengths of strip togetherwith the circular portions overlapping throughout approximately halftheir circumference, placing end cups over the ends of the telescopes,assembling a plurality.

of tubes into engagement with said openings and bonding the tube andheader structure together with a sealing medium.

' 2. The method of forming heat exchange devices Which comprises thesteps of forming headers by forming a pair of channel-like strips, eachstrip having a substantially circular segmental cross-section and anopen longitudinal side and one strip having a plurality of tube engagingopenings along one wall thereof, telescoping said strips together withthe circular portions overlapping throughout approximately half theircircumference, forming iin and tube heat exchange cores, assemblingthe'tube ends of said cores into engagement with said openings, placingend cups over the ends of the telescopes, and bonding each entire heatexchanger together by a single fused metallic sealing operation.

3. The method of forming a heat exchange device Which comprises thesteps of forming a header by forming a pair of channel-like strips, eachstrip having a substantially circular segmental cross-section and anopen longitudinal side and one strip having a plurality of tube engagingopenings along one wall thereof, longitudinally telescoping said pair ofstrips together with the circular portions overlapping throughoutapproximately half their circumference. forming a fin and tube heatexchanger core, assembling the tube ends of said core into engagementwith said openings and bonding the entire exchanger together by a singlefused metallic sealing operation.

J OI-IN KARMAZIN.

